This invention generally relates to the art of electrical connectors and, particularly, to an electrostatic discharge system for electrical connectors.
An electrical connector often has a mating end at which conductive terminals are exposed for engagement with the terminals of a complementary mating connector. For instance, the connector may include a receptacle within which contact portions of the terminals are exposed for engagement with the terminals of a complementary plug connector. If an individual touches one or more contact portions of the terminals, as with the person""s finger, an electrostatic charge may be created and discharged through the terminals and damage may result to interior components with which the connector is electrically coupled.
In order to avoid such problems with electrostatic charges, various types of means have been proposed, such as mounting shutter plates at the mating ends of connectors to prevent accidental engagement with the contact portions of the terminals. In addition, Japanese Patent Laid-Open No. 11-259617 discloses a plate-like conductive member mounted at the mating end of an electrical connector and connected to a metal cover so that an electrostatic charge, if any, is discharged by the conductive member to the metal cover.
Electronic components, such as integrated circuits for a portable information terminal set, are usually mounted on printed circuit boards or flat flexible cables which, in turn, are disposed in a connection end of an electrical connector that is installed in the terminal set. However, efforts have not been successful in providing electrostatic discharge prevention means for the electrical connector and the printed circuit board or flat flexible cable. Accordingly, when connecting or disconnecting the electrical connector or the printed circuit board or flat flexible cable, electrostatic charges may cause damage to the electronic components such as the integrated circuits. Any efforts have involved grounding shields which are soldered directly to the printed circuit board or the shield has an integrated terminal arm engageable with the printed circuit. The use of solder is not always the best choice since solder is an additional process which adds to the cost of manufacture. In addition, because soldering processes require heat, which can damage nearby components, the soldering process must be highly controlled to avoid damage. Manufacturing a shield with an integral terminal arm having a consistent contact pressure on a flexible printed circuit also is very difficult to manufacture. The present invention is directed to solving these problems in a solderless electrostatic discharge system for such connectors.
An object, therefore, of the invention is to provide an electrical connector with a new and improved electrostatic discharge system.
In the exemplary embodiment of the invention, an electrical connector includes a dielectric housing having a connector mating face and a circuit board receiving face. A plurality of conductive terminals are mounted in the housing. Each terminal includes a contact end generally at the connector mating face of the housing and a board-engaging end generally at the circuit board receiving face of the housing. At least one of the terminals is a ground terminal. A metal shield is mounted on the housing about at least the connector mating face thereof. An intermediate conductive terminal is mounted on the housing and includes one end engaging the metal shield and an opposite end engaging the ground terminal.
As disclosed herein, one end of the intermediate terminal abuts against an inner surface of the metal shield. An opposite end of the intermediate terminal abuts the ground terminal. Solder connections are completely avoided.
According to one aspect of the invention, the intermediate terminal includes a resilient portion between its opposite ends to provide a contact pressure with the metal shield and the ground terminal. In the exemplary embodiment, the resilient portion is generally S-shaped. The intermediate terminal may be stamped and formed of conductive sheet metal material, with the S-shaped resilient portion being generally planar. The opposite ends of the intermediate terminal are formed to extend out of the plane of the S-shaped resilient portion.
According to another aspect of the invention, the intermediate terminal is disposed for free movement within a groove in the housing. The resilient portion of the terminal is located substantially in the groove. The opposite ends of the intermediate terminal are exposed at opposite ends of the groove for engaging the metal shield and the ground terminal.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.